Damage to the surface of a dielectric layer in a semiconductor structure following a chemical-mechanical planarization (CMP) process is often observed and causes a negative impact on the reliability of one or more interconnects (metallic conductors) formed in the semiconductor structure. This damage is typically caused by the polishing fluid used during the CMP process, and is critically adverse when the dielectric layer is formed with an ultra-low-k (ULK) dielectric material, where k represents the dielectric constant.
Further, an alloy element (e.g., based on aluminum (Al), manganese (Mn), etc.) has been implemented in advanced copper (Cu) interconnects of semiconductor structures for electromigration (EM) resistance enhancement. EM is the movement of ions in a conductor due to the momentum transfer between conducting electrons and diffusing metal atoms, which can lead to reduced performance and even failure of interconnects. However, it has been observed that the lack of alloy element segregation onto the Cu surface degrades the EM resistance enhancement otherwise expected by the introduction of the alloy element.